One object of this invention is to provide a particular multistation press for producing relatively large vehicle body parts.
Multistation presses of this type have press stations in which forming tools (consisting of a top tool and a bottom tool) are arranged. During operation, the sheet metal parts are transferred from press station to press station in order to be formed step-by-step. While the first press station is usually a drawing station, in which a relatively pronounced workpiece deformation takes place, the dimensional changes in the press stations which follow are usually much less pronounced. The forces required for this purpose act correspondingly.
Multistation presses with separate, mutually linked press stations, if they are set up for machining relatively large sheet metal parts, have very large dimensions and are therefore correspondingly expensive. It is an object of this invention to minimize the space required for the press as well as costs.
As described in German Patent Document DE 42 21 143 A1, this has been attempted by constructionally combining the press stations which follow the drawing station. For this purpose, the press frame is constructed on two transversely arranged main supports on which a bedplate is placed in the passage direction which spans two work stations. Bottom tools assigned to the individual work stations are arranged on the bedplate arranged in the longitudinal direction. Above the bedplate, two press slides, which are arranged behind one another in the longitudinal direction, are held so that they can be moved up and down and are driven in an up-and-down swinging manner by respective separate head pieces. The head pieces are disposed on longitudinal traverses which extend continuously on the right and the left side and which, in turn, are set up by a total of four press stands on the cross traverses which extend below the bedplate.
The longitudinally extending bedplate, which is disposed at its forward and rearward end, as well as the longitudinally extending traverses which carry the head pieces, results in a very heavy construction, particularly if the press is to machine relatively large sheet metal parts and therefore itself has relatively large dimensions.
From European Patent Document EP 0 581 008 A2, a similar press system is known having press stations following the drawing station which are serviced by a common slide. In this slide, which is an exterior slide, so-called interior slides are disposed in a vertically displaceable manner and can be adjusted separately.
In this press system, which uses the same basic concept as the previously described press system, in the case of relatively large press dimensions, the required stabilities of the supports extending in the longitudinal direction and of the longitudinally arranged bedplate can be achieved only by using large amounts of material.
From German Patent Document DE 33 22 377 A1, a multistation press which has a press frame that has several so-called upper stand parts which are set up on a bedplate extending in the longitudinal direction and by which two platforms are carried which extend in the longitudinal direction is known. The platforms form longitudinal supports between which two head pieces are held for driving the slides arranged underneath.
Concerning the press frame, the statements apply which were made in conjunction with the above-mentioned state of the art.
From German Patent Document DE 42 32 604 A1, a multistation press is known in which press frame with several slides of different lengths are disposed behind one another in the longitudinal direction. A separate bedplate and an individual head piece is assigned to each slide, with the head piece and the bedplate extending along the whole length of the slide. If the slide is to span several press stations, for the above-mentioned reasons, then an unacceptably high press weight and manufacturing expenditures will result.